The present disclosure relates to back-and-forth displacement detecting devices for detecting back-and-forth movement and information processing devices with the same and particularly relates to a technique for simplifying arithmetic processing for determining back-and-forth movement. Furthermore, the present disclosure relates to portable information processing devices with display sections and particularly relates to a technique for switching among displays on the display section.
For example, in a general portable information device, a plurality of acceleration sensors are attached to the upper, lower, left, and right sides thereof and the acceleration sensors detect accelerations produced by turning operations of the portable information device. Then, a CPU of the portable information device determines, based on the acceleration detected by each acceleration sensor, a turning operation of the portable information device and executes an instruction on a character input and a character conversion which are assigned to the turning operation.